Lipoamino acids are a class of molecules first identified in bacteria that consist of a fatty acid moiety conjugated to an amino acid (Kawazoe et al., J. Bacteriol., 173:5470-5475, 1991). At least three fatty acid-amino acid conjugates are natural constituents of the mammalian brain: N-arachidonylglycine (NAGly), N-arachidonyl-4-aminobutyric acid (NAGABA), and N-arachidonylalanine (NAAla). NAGly is an endogenous constituent of many tissues, including spinal cord, small intestines, kidneys, glabourous skin, heart, lung, liver, spleen, testes, and blood (Huang et al., J. Biol. Chem., 276:46, 2001). NAGly is a structural analog of the endogenous cannabinoid anandamide, although it has been reported to lack affinity for the cannabinoid receptors CB1 and CB2, the vanilloid VR1 receptor, and the anandamide transporter (Huang et al., 2001, supra; Burstein et al., Prostaglandins and Other Lipid Mediat., 61:29-41, 2000). NAGly has been reported to have analgesic properties.